Device for adjusting the suspending point of a suspended object

ABSTRACT

THIS INVENTION CONCERNS A DEVICE FOR AUTOMATICALLY ADJUSTING THE SUSPENSION POINT OF A SUSPENDED OBJECT, E,G., OF A CONTAINER SUSPENDED IN A CRANE, BY DISPLACING A SUSPENSING BLOCK ALONG A BEAM MOUNTED ONTO SAID OBJECT SO LONG AS TO BRING THE SUSPENSION POINT OF THE OBJECT INTO A DESIRED POSITION RELATIVE TO THE CENTER OF GRAVITY OF THE OBJECT. THE INVENTION CONSISTS OF GRAVITY OPERATED MEANS SENSING THE POSITION OF THE OBJECT AND CONTROL MEANS ACTUATED BY THESE SENSING MEANS TO CONTROL THE CONNECTION AND DISCONNECTION OF A SOURCE OF POWER AND A DRIVING MECHANISM OPERATING THE DISPLACEMENT OF THE SUSPENDING BLOCK ALONG THE BEAM OR, IN COMBINATION, THE DISPLACEMENT OF THE SUSPENDING BLOCK ALONG THE BEAM AND OF THE BEAM RELATIVE TO THE OBJECT. THE MAIN EMBODIMENT COMPRISES A VERTICAL BAR HINGED TO THE SUSPENDING BLOCK AND TO THE SUSPENSION OR HOISTING DEVICE, SENSING MEANS BEING PROVIDED FOR SENSING THE ANGLE BETWEEN SAID BAR AND ARMS FIXEDLY MOUNTED ON THE SUSPENDING BLOCK AND ACTUATING CONTROL MEANS CONTROLLING THE ACTION OF THE DRIVING MECHANISM.

Jan. 26, 1971 MATTSQN 3,558,175

DEVICE FOR ADJUSTING THE SUSPENDING POINT OF A SUSPENDED OBJECT Filed Aug. 20, 1968 3 Sheets-Sheet 1 zwzmiiw q MM Jan; 26, 1971 A MATT $QN 3,558,175

E FOR ADJUSTING THE SUSPENDING POINT OF A SUSPENDED OBJECT Filed Aug. 20, I968 ssheet -sheet a FIG.2

Xvi/V516 Jan. 26, 1971 J. A. MA TTSON 3,558,175

DEVICE FOR ADJUSTING THE SUSPENDING POINT OF A SUSPENDED OBJECT Filed Aug. 20, 1968 43- Sheets-Sheet wiwu m/aw rive laws 3,558,175 DEVICE FOR ADJUSTING THE SUSPENDING POINT OF A SUSPENDED OBJECT Johan Arne Mattson, Vasteras, Sweden, assignor to Paul Anderson Industries Aktiebolag, Vasteras, Sweden, a corporation of Sweden Continuation-impart of application Ser. No. 645,374, June 12, 1967. This application Aug. 20, 1968, Ser. No. 754,089 Claims priority, application Sweden, June 15, 1967, 8,177 67 Int. Cl. E66c US. Cl. 294-67 4 Claims ABSTRACT OF THE DISCLOSURE This invention concerns a device for automatically adjusting the suspension point of a suspended object, e.g., of a container suspended in a crane, by displacing a suspending block along a beam mounted onto said object so as to bring the suspension point of the object into a desired position relative to the center of gravity of the object. The invention consists of gravity operated means sensing the position of the object and control means actuated by these sensing means to control the connection and disconnection of a source of power and a driving mechanism operating the displacement of the suspending block along the beam or, in combination, the displacement of the suspending block along the beam and of the beam relative to the object. The main embodiment comprises a vertical bar hinged to the suspending block and to the suspension or hoisting device, sensing means being provided for sensing the angle between said bar and arms fixedly mounted on the suspending block and actuating control means controlling the action of the driving mechanism.

This application is a continuation-in-part application of my copending application Ser. No. 645,374, filed June 12, 1967, now abandoned and entitled Device for Adjusting the Suspending Point of a Suspended Object.

It is known to suspend a load in a hoisting device by means of a suspending block displaceable along a beam which is itself capable of translatory movements in a frame in which the load can be mounted (US. patent specification No. 2,772,794). It is further known to displace a suspending block along a beam by means of a power driving mechanism (US. patent specification No. 2,925,300).

The invention is especially concerned with the problems arising in connection with the handling of large containers, often heavily loaded, especially with the loading and unloading of containers in a port or railway station where a rapid and easy handling is an economic neces sity and where the lowering of the containers must be effected in a position exactly adapted to the position of the supporting surface, e.g., the hatch or deck of a boat or the platform of a railway car or lorry so as to avoid damages to these surfaces to the container and/or to the load. Since the load of a container is not visible from the outside, there are difficulties in estimating the position of the center of gravity of the load and to adjust the position of the suspension point by eyesight.

The invention consists in a simple and efiicient device for automatically controlling the displacements of the suspending block into a position resulting in a desired pre-set position of the load relative to the horizontal plane.

For this purpose gravity operated means for sensing the position of the load relative to the horizontal plane United States Patent 0 "ice comprise control means for connecting a driving mechanism adapted to operate the displacement of the suspending block to a desired position when the position of the frame differs from a desired position relative to the horizontal direction.

Preferably the driving mechanism comprises an electric motor which is driving a transmission member cooperating with the suspending block or which is mounted on the block and co-operates with a rack or the like on the beam by means of a gear for the displacement of the block, the control means being then electric contacts actuated by the sensing means.

A simple and strong construction is obtained by using as sensing means a bar hinged with its lower end to the lifting eye of the suspending block and with its upper end to the lifting member of the hoisting device, arms fixedly mounted onto the suspending block and extending in the directions of possible movement of the block, stays of resiliently variable length connecting the ends of said arms and the upper portion of the bar and contacts operated dependent of the length of the stays when said length differs from that corresponding to the desired position of the arms and hence of the frame and the load.

Sensing means are preferably disposed in different vertical planes, the control means of which correspondingly operate first driving means for the displacement of the suspending block along the beam, and second driving means for the displacement of the beam in the frame. According to an embodiment of the invention, the beam is rotatably mounted on the frame so that the suspending point can be adjusted into any position Within the circular area which can be covered by the rotating beam.

An example of an embodiment of the invention is described hereinafter with reference to the accompanying drawings.

FIG. 1 shows a side elevation of a device for adjusting the suspension point to which the automatic control means are to be adapted. FIG. 2 is a plane view of the device according to FIG. 1. FIG. 3 shows a general side elevation, partly in section, of the automatic control means. FIG. 4 shows a longitudinal section of a level control member.

In FIGS. 1 and 2 a lifting frame 1 is by known means, only symbolically shown at 2, rigidly connected to the top of a container 3. The lifting frame 1 is by four legs 4 rigidly connected to a circular guideway 5 presenting an U-shaped profile open toward the center of the guideway and situated in a plane parallel with the plane .of the frame 1. A beam 6 placed along a diameter of the guideway 5 is at its ends provided with rollers 7 adapted for travelling in the guideway 5. The beam 6 is kept in its diametral position in the guideway by lateral arms 8 forming a cross together with the beam and having at their ends rollers 9 co-operating with the guideway 5. The beam 6 is formed of two parallel U-profiles turned with their webs toward each other and leaving between them a narrow slot-like space. This slot-like space forms a guiding slot 10 for a block 11 situated beneath the beam and having fixed thereon a lifting eye 12 extending upward through and above the slot-like space. A drive mechanism for rotating the beam 6 in the circular guideway 5 consists of a bracket 13 mounted on one end of the beam, a motor 14 mounted on said bracket and a gear transmission 15 between the shaft of the motor and the roller 7. For the displacement of the block 11 along the guiding slot 10 there is beneath the beam 6 a screw or rack 16 co-operating with a nut or a gear respectively, not illustrated, which is drivingly connected with a motor 17 mounted on the block 11.

The device illustrated in FIGS. 3 and 4 is according to the invention provided for an entirely automatic adjustment of the suspending point into a position in which the container hangs in horizontal position or at any predetermined inclination. This device comprises an arm cross 18 fixedly mounted on the lifting eye 12 above the beam 6, i.e. fixedly connected with the block 11. The lifting eye 12 is hinged onto a bar 19 having at its upper end an eye 20 capable of being hooked onto the lifting hook of the crane. The ends of the arms of the cross 18 are connected by stays 21 with the upper portion of the bar 19. In these stays are mounted resilient members 22 permitting a limited extension or shortening of the stays.

The structure of the resilient member is shown in FIG. 4. Each stay 21 is divided in two portions 21a and 21b having their adjacent ends mounted each onto the bottom portion 23 and 24, respectively, of one of two cylindrical sleeves 25 and 26, respectively. The outer diameter of sleeve 26 is made to slidably fit into the inner diameter of the outer sleeve 25 whereby the stay portions 21a and 21b are slidably guided on each other in longitudinal alinement of each other. A spring 27 is inserted with an initial compression within the sleeves between their bottom portions 23 and 24. A contact 28 is mounted on an insulating member 29 onto the outer sleeve 25 and extends through an opening 30 therein within reach of the inner sleeve 26. In the normal position of the sleeves corresponding to the desired position of the frame, e.g. the horizontal position thereof, the contact is outside the end of the inner sleeve 26. This contact is connected to one branch of the feed circuit 31 of one of the motors 14 or 17, the other branch of which is connected to the sleeve 25. Contact 28 and sleeve 26 thus form a switch which is open in the said normal position shown in FIG. 4.

The switches 26, 28 of the two resilient members 22 of the stays connected to the arms extending in the direction of the beam 6 (FIG. 3) are connected to the motor 17 operating the displacement of the block 11 along the beam 6 in such manner that when the switch of one of said two members is closed, motor 17 is energized to rotate in one direction, and when the switch 26, 28 of the other member 22 is closed, motor 17 rotates in the opposite direction so that the block 11 can always be automatically returned to a position situated in a vertical plane through the center of gravity of the load at right angles to the beam 6. The switches of the two resilient members 22 of the stays connected to the arms extending transversely of the beam 6, i.e. the arms 18 shown in FIG. 3, are connected to motor 14 which in a similar manner is controlled to operate the rotation of the beam to bring the suspending eye of the block 11 exactly above the center of gravity of the container 1. The details of such interconnections of the switches 26, 28 and motors 14, 17 need not be described in detail, such electric couplings lying within the elementary knowledge of electrical engineering.

The construction might in practice depart from the embodiment described above and illustrated in the drawings. The means sensing the position of the frame relative to the horizontal plane can be of any kind appropriate for the purpose of the invention. When using resilient members 22 actuating control contacts, the guiding of the portions of the stays in their longitudinal alinement relative to each other need not necessarily have the form of sleeves slidingly guided one within the other. The contacts may be, and preferably are, adjustable in position on the outer sleeve or stay portion to pre-set any desired inclination of the frame and container within practical limits.

What I claim is:

1. A device for automatically adapting the suspension point of a load suspended by a lifting member especially of a container suspended in a hoisting device to the center of gravity of the load, comprising, a lifting frame mounted onto said load, at least one guide beam mounted on said frame, a suspending block with a lifting eye movably guided along said beam, driving means movable along said beam for the displacement of said suspending block, a motor actuating said driving means, a power circuit for said motor, arms fixedly mounted on said suspending block and extending in the direction of its possible displacement, a link bar connected at its lower end to said lifting eye and at its upper end to said lifting member, stay members with their lower ends connected to the ends of said arms and their upper ends connected to the upper portion of said link bar, each of said stay members comprising two portions longitudinally displaceable relative to each other, spring means opposing relative longitudinal displacement of said two portions, contact means supported by each of said portions and connected to said power circuit of said motor to energize said circuit when said arms and said bar are not in a position relative to each other corresponding to the desired position of said frame and the loads relative to the horizontal position.

2. A device for automatically adapting the suspension point of a load suspended from a lifting member to the center of gravity of the load, comprising, a suspending frame fixedly connected to the load, a guide beam mounted on said suspending frame, a suspending member guided by said guide beam for longitudinal parallel displacement along said guide beam, a motor driven mechanism connected by transmission members to said suspending member for effecting its displacement along said beam, means for sensing the position of the frame relative to the horizontal direction and for controlling said motor driven mechanism, said means including a link bar linked to the suspending member and to the lifting member and a control device connected between said link bar and said suspending member and responsive to changes in the angle between the link bar and the suspending member for controlling said motor driven mechanism so as to re-establish a desired position of the suspending member and the load when the angle between the link bar and the suspending frame differs from a preset value.

3. A device for automatically adapting the suspension point of a load suspended from a lifting member to the center of gravity of the load, comprising, a suspending frame unmovably connected to the load, a guide beam movably attached to said frame, a suspending member movable along said guide beam, a first power driven driving mechanism for the displacement of the suspending member along said guide beam, a second power driven driving mechanism for the displacement of the beam at an angle in its longitudinal direction with respect to said frame, means for sensing the position of said frame rela tive to the horizontal direction, said means comprising a link bar linked to the suspending member and to the lifting member and control devices responsive to changes in the angles between the link bar and the suspending frame in two different vertical planes and comprising adjustable control means controlling said power driven means to re-establish the desired position of the load when the angles between the link bar and the suspending frame in said planes differ from pre-set values.

4. A device for automatically adapting the suspension point of a suspended object to the center of gravity of said object comprising a suspending frame unmovably connected to said object, a guide beam mounted for rotation in a plane parallel with said frame, a suspending member movable along said beam, said suspending member having a lifting eye, a first motor driven driving mechanism for the displacement of said suspending member along said beam, a second motor driven driving mechanism for rotating said beam on said frame, said motors having power circuits, means for sensing the position of the frame relative to the horizontal position in two different directions, said sensing means comprising cross arms fixedly mounted onto said suspending member, said cross arms having free ends, stay members with one end connected to said free ends, a link bar with its upper end connected to the upper ends of said stays and whose lower end is hinged to said lifting eye on said suspension member, said stays each comprising two portions longitudinally displaceable relative to each other, spring means opposing relative longitudinally displacement of said two portions, contact means supported by each of said portions and connected to said power circuit of said motors to energize said circuits when said arms and said bar are not in a position corresponding to the desired position of the frame and the load relative to the horizontal position.

6 References Cited UNITED STATES PATENTS 10 HARVEY C. HORNSBY, Primary Examiner U.S. Cl. X.R. 

